Legionella pnciiinoplula sp. nov.: Tlie Legionnaires' Disease Bacterium 



Table:. 



DNA relatedness of LDB strain Philadelphia 1 to organisms 



of similar guanine plus cytosine content and organisms isolated 



from patients with high serum titers to LDB 



7r relatedness to LDB strain Philadelphia L' 

 Source of unlabeled DNA 60°C 75°C 



Rochalimaea quintana ATCC VR35ii 5 U 



Flavobactehum meningosepticum 2 



FlavobacteriumW^^'S.X^O 3 



Flavnbacteriitm IIB B6829 3 



Francisella tularensis 4 1 



Yersinia entewcolitica 498-70'' 



Y. enterocolirica 27^ 



Y. entewcolitica 1474'' 



Y. entewcolitica 481^ 



Y. entewcolitica 867'' 4 



Y. pseudotuberculosis P262 



Y. pseudotuberculosis P27 



Pasteurella haemolytica KC228 3 



P.multocida ATCC 12947 1 



P. multocida ATCC \0544 1 



P. multocida ATCC 6535 



P.ureaeKC5\8 1 4 



Cytophaga johnsonae AJCC 29586 2 



Cylophagajohnsonae ATCC 29588 



Fle.xibacter canadensis V ASM 9D 



Microcyclus major B859 3 



a DNA reassociation in homologous Pluladelplua 1 was approxnnately 70'; in 60°C reactions and 60';f in 75"C" reactions. 



b There are four different DNA relatedness groups among strains presently called Yersinia cnterocolitica {3). These groups are 

 characterized by their reactions for sucrose (sue), rhamnose (rha), raffinose (raf), and melibiose (mel). Y. enterocolitica sU-d'uK 

 498-70 and 27 give the typical fermentation pattern: suc+, rha-, raf-, mel-. Strain 1474 is atypically sue-. Strain 48 is 

 atypically rha-i-, raf-t-. meH. Strain 867 is atypically ^ha-^. 



Pasteurella ureae and LDB were 7% related in 60°C reactions and 4% related in 75°C 

 reactions. DNA relatedness of Philadelphia 1 to all these organisms at 60°C was 5% or less (Table 

 2). None of these values below 5% was considered significant. Therefore, the LDB is not related 

 to any of these organisms at the species or genus level. While )'. pestis was not directly ruled out, 

 it is more than 90% related to Y. pseudotuberculosis (13) and can be ruled out indirectly. 



The time required for reassociation was similar for LDB DNA and DNA from E. co//K-12. 

 DNA from this E. coli strain has a molecular weight of 2.5 X 10' daltons. Therefore, LDB DNA 

 is also approximately 2.5 X 10' daltons; enough genetic information to specify some 3,000 

 genes. Isolates of LDB are extremely similar in growth, serology, biochemical tests, fatty acid 

 composition, and antibiotic susceptibility profiles (77. 75. 7iS'). DNA relatedness was detennined 

 for 15 of the LDB isolates available at the Center for Disease Control (CDC) to see if these 

 relatively few phenotypic markers reflected similarity over the entire genome of LDB. Most 



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